i've had the "call in" problem before. i spoke with one of those 1K angels who basically said the best way to deal with it is to make an entirely new itinerary at the new, lower price, put it on hold, and then had them manually re-ticket, applying your existing ticket's value and sending you a voucher for the difference. she even waited on the phone while i scrambled to put an itinerary on hold, and she saw it right after i held it. and she even managed to keep my upgrades for me.

this is why i try to call at a time of day when i'll get the HNL call center!